PLATYSMA.] CKTRARlKf. 227 



Form 2. ampullaceum Cromb. Linn. Soc. Jour*?. Bot. xvii. 

 (1880) p. 572. Thiillus vesiculoso-inflated either towards tht 

 apices of the latinise, or hero and there throughout. Apothecia 

 never seen. Lichen ampullaceus Linn. Sp. PI. (1753) p. J 146 ; 

 Huds. Fl. Angl. p. 450; With. Arr. ed. 3, iv. p. 6L. Liehenoules 

 tinctorium glabrttm resiculosum Dill. Muse. 188, t. 24. f. 82. Li- 

 chenoides saxatile tinctorium foliis latioribus uon pilosis, vesintlas 

 proferens Dill, in Ray, Syn. ed. 3, p. 74, n. 71. 



A monstrosity, caused by the presence of the parasite Abrothallw 

 f>>nif/iii. The portions of the lacinise which are the host become more or 

 less bullato-inflated (var. bulletin Schaer, Enum. p. 13). These -'inflated 

 vesicles" were mistaken by Dillenius and older authors for apothecia. 



Ilab. On shadv rocks in upland situations. Distr. Local and scarce in 

 N. England (where it was originally detected near Coin, in Lancashire), 

 and among the N. Grampians. B. M. : Craig Cluny, Braemar, Aber- 

 deeiishire. 



A T ar. /3. tenuisectam Cromb. Grevilleaxv.(1886)p. 49. Thallus 

 dark-glaucous or brownish-black above, blackish beneath : laciniae 

 short, narrow, much divided and crowded. 



A distinct variety, presenting a panniform aspect. The darker colour 

 of the thallus is probably owing to the habitat. It is seen only in a 

 sterile condition. 



Hub. On exposed boulders in mountainous regions. Distr. Rather 

 local, though not uncommon in W. England, N. Wales, among the 

 Grampians, and the N.W. Highlands of Scotland. B. M. : Stiperstones, 

 Shropshire; Clougha, Lancashire; Rhewgreidden, Merionethshire. Crian- 

 larich and Ben Lawers, Perthshire ; Mori-one, Braemar, Aberdeenshire ; 

 Glen Nevis, Inverness-shire ; Hills of Applecross, Ross-shire. 



12. P. lacunosum Nyl. Mem. Soc. Cherb. v. (1857) p. 100 ; 

 Syn.i.p.314. Thallus foiiaceo-expanded,reticulato-laumose, broadly 

 laciniate, or laeiniato-lobed, glaucescent or greyish-white, beneath 

 blackish or pale-brown towards the circumference; laciniae crenato- 

 undulate and incised, rotundate at the apices ^+ jellowish , CaCl~). 

 Apothecia elevated, moderate or large, reddish-brown, the margin 

 entire ; spores ellipsoid, 0,006-8 mm. long, 0,004-5 mm. thick. 

 Carroll, Journ. Bot. 1865, p. 288 ; Cromb. Lich. Brit. p. 27 ; Leight. 

 Lich. Fl. p. 103, ed. 3, p. 98.Cetraria lacanosa Ach. Meth. (1803) 

 p. 295. 



Distinguished from the preceding, some states of which it closely re- 

 sembles, by the much broader and rounded lacinise, with their reticulato- 

 rugose upper surface. The thallus is frequently more or less isidiiferous, 

 sometimes densely so, when growing in moist places. On dry exposed 

 rocks it is of a dark-chestnut colour, as if it had been scorched. The 

 apothecia have not been found in this country, but the spermogones, 

 which are similar to those of PL ylaucum, occasionally occur. 



Hob. On shady rocks in subalpine districts. Distr. Local in the S.W. 

 and Central Highlands of Scotland, chiefly among the Grampians. B.M. : 

 Glen Falloch. Ben Lawers, and Craig Calliach, Perthshire ; Craig Cluny 

 and Morrone, Braemar, Aberdeenshire; near Fort William, Inverness-shire. 



Q2 



